It definitely matters. Watch some of the teardowns of power adapters on YouTube: they look and work almost identically and you’d likely never tell the difference, but one is much more likely to set your house on fire if it malfunctions.
Stuff my nightmares are made of now. Anyway, I always open all power adapters/supplies I buy from there, because my original education is EE, so I never used these. But the idea that some people are using such things is quite scary.
Not to poo poo on aliexpress itself. There are some exceptional quality sellers and products to be found there. You just have to know how to find them.
https://www.redpoints.com/blog/amazon-commingled-inventory-m...
You're making the point I'm making. While I don't (to the best of my knowledge) purchase counterfeit items, I don't pretend that certification is anything other than certification. Hopefully certification comes with standards, and aren't self-reporting... but that's not always the case.
Only when a case goes to court, it will be determined if the certification was rightful or not.
https://support.ce-check.eu/hc/en-us/articles/360008642600-H...
I opend some of them non-destructively to check them out, and deemed them sufficient. They barely get warm at all.
Nonetheless I put them in some closed rack where they only could produce some stink, but no fire.
I'm too lazy to unplug them right now to upload photos to Imgur, or such, because it would disrupt some services.
Anyways, no urban legend. Just the usual bureaucratic disconnect from reality, saying otherwise.
Meanwhile another bureaucratic entity, the german customs really likes to hassle you because of exactly that sh..! :-)
edit: Some of them in continous operation for just over a decade, some others about 5 to 6 years, YMMV. (shrug)